Fertility is one of the most important health care aspects in the society. Fertility and fecundity are associated with several factors such as psychological, environmental and chemical factors. The increasing influence of environmental factors and knowledge about the associated risks to such factors are leading to a growing need for methods by which the fertility of the population can be assessed without significant encroachment of the personal circumstances of test persons. The lack of available methods for fertility screening for women is referenced in Reproduction Toxicology (1990), Vol. 4, Pages 1-2. Measurement methods for the evaluation of the menstrual cycle and fertility of women that will not encroach on their daily routines are lacking.
Determining fertility either for family planning or for contraception is a critical approach of the female health care system, and precise determination of ovulation is required. So far, some indirect methods to determine the ovulation in women are based on serum hormone levels or measurement of the basal body temperature. The method using serum hormone levels is reliable, but the wide employment of laboratory diagnostic methods that are required for these measurements (such as in urine) leads to substantial costs. Otherwise, a postovulatory rise in the temperature of about 0.5° C. (+/−0.1° C.) has been documented in the evaluation of the course of the menstrual cycle. This temperature rise is due to the circadian variations of the body core temperature amount to ±0.5° C.
DE 3223657 C2 and DE 19524966 A1 describe a measurement of the temperature with an apparatus worn on the wrist of a user. The described devices are able to save the data values and to determine ovulation. These methods and devices exhibit the following practical disadvantages: low reliability due to the disruptive influences of the ambient temperature. Additionally, these methods measure basal body temperature measured after waking-up in the morning. The experience with these methods has demonstrated a low efficacy of the data values considering the irregular daily routines of many patients.
The disruptive influences are avoided by measuring core body temperature in the vaginal canal. DE 9215558 U1 describes a device for measuring the basal body temperature in the vaginal canal which telemetrically transmits the collected data to an external memory medium.
A sensor that is connected to a processor that samples and stores the temperature data for determination of the ovulation condition is described in EP 0667118A1 and in DE 3211573A1. The basal body temperature in the vaginal canal of a user is determined and then transferred over a cable to an external memory unit.
U.S. Pat. No. 5,209,238 describes a multi-sensor for ovulation monitoring positioned in the vaginal canal and thereby allows the measurement of LH concentration, pH value and density of vaginal secretion as well as the basal body temperature. An ovulation predictor based on redox potential in vaginal secretion is described in U.S. Pat. No. 4,753,247. Likewise, U.S. Pat. No. 4,498,481 describes an electrical conductivity of vaginal secretion detector. In U.S. Pat. No. 4,827,946, a ring-formed pessary with polarized electrodes is suggested for contraception that would impede the advancement of male germs via the build-up of an electrical field.
Devices described above that can be placed in the vaginal canal (U.S. Pat. Nos. 5,209,238; 4,577,640; and 4,498,481)—although they avoid the disruptive influences—are uncomfortable for patients. Their form and size are not suitable for long-term use, because the flow of secretion is hindered in the vaginal canal. Even in short-term use, devices with inflexible casings (U.S. Pat. No. 4,827,946) or higher weight reduce wearing comfort. Measuring methods that rely on discontinuously ascertained values in urine or in breath can be error-prone if they are carried out by untrained personnel. Such methods are inherently deficient also in that the measurement interval cannot be selected to be arbitrarily small.
A medical device suggested for contraception is described in patent U.S. Pat. No. 4,292,965. This intra-vaginal ring for use as a contraceptive includes a medical layer and is placed inside the vagina for three weeks. Other intra-vaginal rings for contraception are described in U.S. Pat. No. 4,888,074 and U.S. Pat. No. 6,544,546. These intra-vaginal rings are based on the continuous release of a therapeutic agent, such as a hormone.
Patent DE 199 43 456 B4 describes a telemetric ovulation monitoring system for women that determines ovulation in a comfortable medical device to be placed in the vagina and the transmission of data values from a sensor located near where the process of ovulation occurs. This ring pessary is placed anterior to the cervix without obstructing the cervix as described. Additionally, this ring pessary includes a temperature sensor continuously transmitting data values to an external storage device.
The ring pessary described in DE 199 43 456 B4 is a device for ovulation monitoring in women in such a manner that it will be possible to reliably and confidently assess women's menstrual cycles in individual cases, as well as in routine controls, in a cost-effective manner. There is no equipment or devices that must be worn externally on the body. This ring pessary can be placed for up to 6 months. While this ring pessary works reliably over long time periods, the ring pessary changes its optical appearance over time, which is not accepted by some of the users.
The measurement system inside the ring pessary of DE 199 43 456 has to be tightly encapsulated, and the ring pessary is used as a seal. The measurement system has to be exactly positioned inside the ring pessary during the manufacturing process requiring complex, precise, and cost-intensive manufacturing, wherein high pressures are required for encapsulation. These facts increase the likelihood of damage to the ring during the manufacturing process.